The present invention relates to a flat transmission device such as a flat cable assembly and a flat hose assembly and to a method for using the transmission device. Specifically, a flat transmission device includes transmitting members arranged in parallel, in which the transmitting members in each adjacent pair are coupled to each other so that the device has a belt-like structure. The transmitting members include flexible cables for transmitting electricity such as power and signals and/or flexible hoses or tubes for transmitting air pressure or hydraulic pressure.
As such a flat transmission device, a flat cable assembly has been known that includes cables (one example of transmitting members) arranged in parallel. The cables in each adjacent pair are coupled to each other so that the flat cable assembly has a belt-like structure. Flat cable assemblies are used to supply power or signals to movable bodies in facilities such as machine tools. A flat cable assembly has a first end, which is a fixed end fixed to the main body of a facility, and a second end, which is a movable end fixed to a movable body of a facility. The flat cable assembly extends from the fixed end and is reversed at a flexed portion and coupled to the movable body at the movable end. When the movable body moves, the flat cable assembly follows the movable body while moving the flexed portion and supplies power or signals to the movable body.
If a flat cable assembly is used for an extended period of time, aging deterioration of the flat cable assembly gradually reduces the bend radius of the flexed portion. Since the section of the flat cable assembly extends in the air between the flexed portion and the movable body, that section sags due to its own weight. The amount of such sagging gradually increases due to aging deterioration. As the bend radius of the flexed portion of the flat cable assembly decreases, the load on the cables is increased. This shortens the life of the cables. Also, when the sagging of the flat cable assembly becomes great, movement of the movable body causes the sagging section to sway. This can cause the sagging section to contact other parts in the facility or slide along the section between the flexed portion of the flat cable assembly and the fixed end. As a result, the life of the flat cable assembly is shortened.
In the devices of Patent Documents 1 to 6, at least a part of the outer peripheral portion of the flat cable assembly is supported by a supporting member (a belt, a plastic tube, a sleeve member, or a cable guide). This restrains the bend radius of the flexed portion of the flat cable assembly from being excessively small and restrains the section between the flexed portion and the movable body from sagging excessively.